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J. o. MAUBORGNE I :T AL K SISTEM oF RADIO TRANSMISSION Filed June Ie.i920 2 Sheets-sheet 1 A O)D)))))))))))))))/)=)Dm- AO))))))))))))))))A22m-m O [gull-.DH1

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J. O. MAUBORGNE ET AL SYSTEM OF RADIO TRANSMISSION Filed June 16 1920 2Sheets-Sheet. 2

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Patented Dec. 2, 1924.

UNITED STATES PATENT OFFICE.

JOSEPH O. MAUBORGNE AND GUY HILL, OF .fifaSHINGTON, DISTRICT 0FCOLUMBIA.

SYSTEINI OF RADIOTRANSMISSION.

Application led June 16, 1.920. Serial No. 389,450.

To alito/1,0m t may concern Be it known that we, Josnrrr O. MAU- noRo-Nnand GUY Hrm, citizens or the United States, and residents or ashington`lin the District ot Columbia., have invented certain new and usefulImprovements in Systems of Radiotransmission.4 or which the following isa spccilication.

This invention relates to the art or radio signaling andv particularlytransmitting racio signals` and a system Jfor use in the practice or'the same.

The oloject 'or the present invention is an improveinent in the. methodand apparatus for transmitting radio signals whereby a simplification inthe equipment required is effected: also more persistent oscillationsare obtained in the case or spark discharge methods and further, thissystem orfers a simple method or obtaining directional sending', and asimple means or generating extremely short wave lengths.

ln the present application oi the art to accomplish radio transmissionan antenna is required and means tor tuning the antenna system toresonance with the frequency or the generator used which 1usuallyrequires complicated and relatively expensive apparatus.

ln our invention we make use of a wave coil ot distriluited inductance,and capacity ou which wave development is produced hy the transmitting'source the wave length or the said wave development depending only uponthe electrical constants ot the coil and the position or the potentialapplication to said coil, the wave coil hy' itself constituting thecomplete antenna system.' In its simplest torm the wave coil is made inthe rorm of a long helix. uniformly wound with suitable insulating wir Lclosely spaced so that the inductancc per unit length relatively large.7e have round that itis desirable to wind the coil Aon a materialhavinc' high insulating properties such as micarta or hakelitedielectro. TV e get theretore, in a comparatively short coil, theequivalent condition or a longl line in the matter or wave development.The electromagneticv waves of the outgoing` signals are omitted fromeach element of the wave coil and we have here a condition where theelectrical constants of the coil. the inductance, capacity. andresistance andE. F, set up therein by excitation from a suitable sourceor energy are all or a distributed character, and the energy is radiatedfrom each element or the coilr` making it accordingly an ideal radiatingsystem.

The fundamental principle underlying the use of the wave coil as atransmitter is that there should he applied at some element or the coil,a maximum potential which will set up waves on the coil or a perioddetermined by the electrical characteristics or the coil and theposition on the coil or the applied potential.

Our system is equally suitable Ytor damped or undamped waves. le may usca high potential discharge method allowing Ytree oscillations to hesetup on the coil, the frequency to he determined hy the electricalconstants or the coil, and the position on the coil of the appliedpotential, or we may impress a high frequency potential on the coil andadjust the coil so lthat its natural wave length should he the same asthat or the source or high potential.

lVe have round that in the use or the discharge method or excitingthecoil, the length oi" the wave or waves set up on the coil depends uponthe position or the point or application oit the potential to the coil.By shifting the point of application or the energysource to differentpositions along the coilal movii o" always in the same direction tromthe e. 4`r. tc-fo dilicrent wave lengths are set up on the coil `toreach position or the application point except that at the exact centeror at either end or the coil, only one wave length is generated. Thetrave lengths generated on the coil are entirely independent or theconstruction or constants or the lead, the spark gap and the associatedcircuits or the source or energy used, but are solely determined hv thecharacteristics of the coil and the position on the coil of the appliedpotential. Then the application point is impressed at the center or thewave coil, each halr ot the wave coil generates the same wave length anda single wave length is transmitted from the coil. Asthe point orapplication is moved away from the center towards either end the shorterpart of the wave coil `generates the shorter wave length determined bythe constants or that part of the coil between the application point andthe end towards which the application point moves. Between theapplication point and the further end of the coil a longer wave lengthis generated depending upon the con-- stants of the coil between theapplication point and the said further end. As the application point iscontinuously moved towards one end, as referred to above, one of thewave lengths is continuously shortened and the other wave length iscontinuously lengthened. Then the application point is applied at theextreme endof the coil, only one wave length is produced which is theV.maximum wave length that the coil can generate. Then the source othigh potential applied to the coil has a Jfrequency of its own, thepoint of contact on Vthe coil is so adjusted that the actual `wavelength oi the coil will be the same as that oit' the source of highpotential, and in this case, only that part of the coil is active, thenatural Ytrequency of which corresponds to the frequency of theimpressed source.

As a source of energy we may use any of the well-known means forproducing high potentials. It may be a Rulnnkorff coil, a high frequencybuzzer, a power buzzer, a high frequency alternator, an are transmitterof an electron ftube transmitter.

Te have also discovered that a wave coil antenna possesses remarkabledirective Qualities. By its use it is possible to transmit signals inany desired direction in space, depending upon the position of the wavecoil with reference to horizontal and vertical planes passing throughthe center of the wave coil. i

Since the electro-magnetic waves emitted by the coil are perpendicularto the longiltudinal axis of the coil, the waves, therefore,

travel in one plane.. The wave coil is equally elfective in transmittingsignals in a vertical plane as in a horizontal plane, and thereforeoifers suitable means for transmitting signals to or from an airplanestation.

Thilo our invention consists primarily in the use of a wave coil andassociated apparatus, without what is ordinarily known as antenna andground connections, our involition also covers the use ol such wavecoils and associated apparatus, with either antennafor groundconnections or both, and this is understood to include the so-calledwiredwireless connections, provided the principle of setting up waves;on the wave coil is used for the purpose of determining the frequency ofthe'transmitted signals.

The principle of operation and the inetlr od oi using our invention canbe better understood by reference to the accompanying diagrammaticVfigures which show practical embodiments of the invention and form partof this specification.

In all of the figures herewith, the same symbols and nomenclature areused :to designate the same apparatus, and therefore reference to thevarious common symbols will not be repeated, except in cases where it isnecessary to nrake clear the diffe-rence bei tween the various figures.

In the accompanying` drawings, Figure l is a diagrammatic view of oneform of :the device used for the transmission of radio signals, in whichan induction coil is used as the energy source;

Figure 2 shows a similar diagrammatic view to'Figure l except that analternator and high tension transformer have been substituted for thebattery andan induction coil of Figure 1 and a condenser shunted aroundthe spark gap; e

Figure 3 shows a diagran'nnatic view sinn ilar to Figure l but indicatesthe use of a continuous wave generator instead of an induction coilcircuit as shown in Figure l;

Figure 4 shows a similar diagrammatic view to that shown in Figure lexcept that connection to the wave coil is electro-static instead ofdirect;

Figure 5 is similar in viewj showing a unilateral electro-magneticconnection to the wave coil; Y u

Figure 6 isa diagrammatic view showing a tuned circuit in inductiverelation to the wave coil;

- Figure 7 is a diagrannnatic view showing an arrangement for excitingtwo 01 more wave coils from the same source;

Figure 8 illustrates another method of exciting two wave coils from'asingle source ci high potential;

Figure 9 shows' a diagrammatic view similar to Figure l except ithat oneside of the spark gap is grounded;

Figure 10 shows a diagrammatic view similar to Figure 3 except that oneside of the continuous wave generator is grounded;

Figure ll shows an arrangement similar to Figure 1 except that -the.wave coil is in the form of an arc.

loo

Having more particular reference to the l drawings and to Figure l, Arepresents the wave coil consisting of a. helix ot suitably insulatedwire, preferably copper, closely wound in a single layer on a suitableinsulating tube. Te `prefer to'make the length ott the helix greaterthan its diameter. P indicates a slider making direct contact with thewave coil and capable of being moved along the wave coil.

S represents a spark gap to the terminals of which are connected theterminals of "the secondary winding H of the induction coil. The sliderP is connected to one terminal of spark gap4 S by a suitable lead asshown. L represents the 'low tension windingof the induction coil and Irepresents the usual iron case. M indicates 1the vibrator for making andbreaking the low tension circuit. B represents a battery and Krepresents a key in the same circuit for purposes of signaling. Theother terminal of the spark gap has no external connection as shown. inthe figure.

The principle of operationis as follows: On signaling by means of thekey K, a high potential is set up across the gap S, one terminal ofwhich is connected to some predetermined point on the Wave coil. Thepotential thus in'ipressed on the coil sets up free oscillations on it,the frequencyY of which is determined by the electrical constants of thecoil and the point of the potential application on the coil.

`We have found that the oscillations developed on such a coil, whenexcited even by a simple induction coil, have extremely small dan'iping,and the radiation from it in the form of a very pure Wave.

Figure 2 shows an arrangement son'iewhat similar to Figure l, exceptthat for the spari; coil of Figure l is substituted a high tension ironcore transformer of which H represents the high tension or secondarywint ing the terminals of which are connected to spark gap S, of anydesired form, which is shunted by a suitable condenser C. L representsthe loiv tension or primary Winding of the transformer, the terminals ofwhich are connected in series with a suitable source of alternatingcurrent, D, of any desired frequency, and a key K, for the purpose ofsignaling.

In the succeeding figures Where coil lil and spark gap S are shown, itis understood that this coil H can either be the high tension Winding ofan induction coil as shown in Figure l, or the high tension Winding of atransformer as shown in Figure 2 and described above.

Figure 3 is similar to Figure l except that the apparatus for applyingpotential to coil A by slider P in this case consists of a generator ofcontinuous Waves. This generator is indicated in the diagram by V. hecircuit connections of this generator are not shown in the figure or inany following' ligures Where a similar arrangen'ient is used as thecircuits of the continuous wave generator do not form a part of thisinvention. lVe are interested merely in attaching to wave coil A adevice so arranged that it Will produce a continuous supply ofoscillating potential suitable to actuate wave coil A. The generator ofcontinuous Waves indicated by V may consist of a high frequencyalternator, an arc transmitter, a vacuum tube transmitter, or any othermeans for generating high frequency oscillations the circuits and thedesign of apparatus in any of the above systems being arranged so that ahigh voltage may be applied to coil A.

It Will be noted, as shown in the figure, that it is not necessary tohave any antenna or ground connection on the coil A or on the generatorof continuous oscillations V, as

i We have found by practice.

In general, if the arrangement of the generator or generator circuitsresul-t 1n the production of a `wave of given frequency, the constantsof wave coil A and the po-f-:ition o slider P should be so chosen as toresult .in the emission of a Wave from War, coil A. of the samefrequency as that applied by 'the generator through the lead to l).

The generator V may consist of an;Y one. of the Well-known forms ofcontinuous Wave apparatus resulting in the production oi eithercontinuous v'aves, interrupted continuous Waves, or modulated contimmusWaves. In the last case the apparatus is modulated either by a buzzer ora inicio phone. Hence, the connection sho Wn in ure 3 may be used eitherfor the prodimtiou of radio telegraphic or radio telephonie signals ofany of the classes described. By the above method ive have transmittedWire less telephone conversation in an entirelyv satisfactory manner.

Figure 4t represents a diagrammatic vieu' of an arrangement similar toFigure l. the only difference being that in Figure T represents acircular metal plate in eloctrolstatic relation to coil A; this circularplate T taking the place of the sliding contact P in Figure l.

Figure 5 is similar to Figure l except that in place of a slidingcontact P there is associated with the coil A a small coil l, oneterminal of which is conncctef to spark gap S. The coil R being sodesigned that it can slide along the entire length of coil A, the coil Rmakin'T an electro-magnetic connection to the coil A. f

Figure 6 .is similar, in general, to Figure 5 except that in this figurethe coil R- is connected to both sides of the spark gan S through aycondenser G1. The circuit 0 R, S is tuned, if desired, to a` Wave lengthcorresponding to the position of coil R on Wave coil A..

Figure '7 is similarI to Figure l except that in this ligure, two coilsA and A1, are excited from one side of spark gap S. lf sliders l?, andP2 are adjusted on their respective coils so as to emit exactly the samevrave length, the intensity of the transmitted signals will be greatlyincreased. This arrangement also enables tivo diiierent Wave lengths tobe transmitted at the same time, if desir-ec, by adjusting, say, sliderP, on coil A2 so that coil A2 Will emit a different Wave length thancoil A1. It is obvious that a multiplicity of coils can be excited inthe same manner.

Figure 8 represents another method of accomplishing the result similarto that shown in Figure 7. In Figure 8 the Wave coils A3 and A4, bymeans of the respective sliders T., and P4, lare connected one to oneside of spark gap S and the other to the other side of spark gap S. Themethod shown of eX citing tivo or more Wave coils from the same sparkgap or other source is an efiicient method for transmitting withconsiderable power on very short wave lengths. The main Vdifficulty intransmitting on short wave lengths in the usual systems is that in orderto obtain an extremely short wave length, the allowable amounts ofinductance and capacity that can be used in timing the circuits are sosmall that it is extremely difficult to get an appreciable amount ofenergy in the antenna or radiating system. This difficulty is obviatedby oui` method as a large number ot wave coils, each proportioned togive an extremely short wave length, can be operated in parallel andtherefore any desired amount of energy can be obtained merely by theaddition of a sufficient number of suitably proportioned coils.

Figure 9 represents an arrangement of apparatus identical with Figure .lexcept that the terminal of spark gap S, which is not connected to thecoil A, is connected to ground. As stated above, with reference toFigure 1, no ground connection is necessary in our system. Te considerhowever, that in certain applications of this system, and in order toget proper potential relations on the Ruhmkorf'f coil, that it may bedesirable to ground one terminal of the spark gap as shown in thefigure. kVVecconsider that under certain conditions, and with certaintypes of wave coil and arrangement ot apparatus, an increased efficiencymay result from the utilization of a ground connection as shown,although by this method we have found that the directional effects aresomewhat neutralized.

Figure 10 is similar to Figure 3 in so far as the apparatus employed isconcerned, but in this case, the source of continuous waves V isconnected to ground as shown in the diagram.

Figure 11 consists of a diagrammatic view similar to Figure 1. In thiscase the coil A is made in the form of an arc or is wound upon a HeXiblerubber tube so that it can be bent in any desired form. This arrangementis of advantage in that the energy is radiated from it in variousdirections which may be desirable in some cases` The abovespecifica-tions and figures are considered to illustrate only some ofthe elementary forms of this invention and its use. Since this inventionprimarily consists in the use of a long coil, ungrounded, and notconnected to any antenna system, all the various forms of connecting itin circuit are not specified herein as they will, in general, be evidentas obvious modifications to anyone skilled in the art.

Among some of the obvious modifications are various forms of winding thewave coil, such as using multiple layer coils instead of the singlelayer herein described.

The slider indicated as T in Figure 4 may have various forms. It may becylinder sliding over thecoil, or some forni of clip for making contactwith a single turn of the wave coil.

We claim:

1. A system for tansmitting radio signals, comprising a power supply andtwo orinore wave coils, means for silnultaneously applying tocorresponding points on said coils a suitable high frequency potentialfrom a single source for causing wave developments on said wave coilsand means for modulating said power supply for the purposes ofsignalling.

2. A system for transmitting radio signals, comprising a powersupply'and two or more wave coils, means for causing wave developmentson said coils upon the siiniiltaneous application to different points onsaid coils, a suitable high frequency potential from a single source forsimultaneous radiating waves of two or more different lengths, and meansfor modulating said lpower supply for purposes of signalling.

3. A system for transmitting radio signals employing a wave coil ofdistributed inductance and capacity in the form of an `open circuit andhaving a non-metallic core,

on whichv wave coil a wave development is produced by the connection ofa source of high frequency to only one element of said wave coil, thewave length of' said wave development depending solely upon theelectrical constants of said wave coil and the elements of said wavecoil to which said high frequency source is applied.

4. A system for transmitting radio signals employing a wave coil ofdistributed inductance and capacity, said wave coil being in the form ofan open circuit and having a. non-metallic core, in which wave coil awave development is produced by the application of a potential to onlyone element of said wave coil, the wave length of said wave developmentdepending solely upon the electrical consta-nts of said wave coil andthe element of said wave coil to which said potance and capacity, saidwave coil being in A the form of an open circuit and having anon-metallic core, on which wave coil a wave development is produced bythe application of a potential to an element of said wave coil, the wavelength of said wave development depending solely upon the electricalconstants of said wave coil and the element of said wave coil to whichsaid high potential is applied, and means for modulating high potentialsource for signalling purposes.

6. A system for transmitting radio signals employing a wave coil ofdistributed inductance and capacity, said wave coil being in the form ofan open circuit and having a non-metallic core, on which wave coil awave development is produced by the application of a high potential toan element of said wave coil, the wave length of said wave developmentdepending solely upon the electrical constants of said wave coil and theelement of said wave coil to which said high potential is applied, andmeans for so selecting the point of application of said high potentialthat the development on said coil is of the same frequency as thatdeveloped in a closed local circuit from which high potential isapplied.

A system for transmitting radio signals employing wave coil ofdistributed inductance and capacity, said wave coil being in trie formof an open circuit and on which a wave development is produced bycausing a high potential from a modulated spark discharge in a non-tunedlocal circuit to be applied to only one element of said wave coil, thewav, length of said wave development depending solely upon theelectrical constants of said wave coil and the element of said Wave coilto which said high potential is applied.

8. A system for transmitting radio signals of a single frequencyemploying two or more wave coils each having distributed inductance andcapacity in the form of an open circuit, each of said wave coils havinga wave development of the same frequency produced by simultaneouslycausing a modulated single high frequency source to be connected tocorresponding elements of said wave coils, the wave length of said wavedevelopments depending solely upon the electrical constants of saidrespective wave coils, and the elements of said coils to which said highfrequency source is applied.

9. A system for simultaneously transmitting the same radio signals ontwo or more frequencies employing two or more wave coils each havingdistributed inductance and capacity in the form of an open circuit, eachwave coil having produced thereon a wave development of diiilerentfrequency by causing a single modulated high frequency source to beconnected to different elements of said Wave coils, the difference inthe resulting wave lengths of said wave developments depending solelyupon the electrical constants of said respective wave coils and theelements of said coils to which said high frequency source is applied.

l0. A system for transmitting radio signals comprising a wave coil ofdistributed inductance and capacity, in the form of an open circuit, ahigh potential source electrically connected to only one element of saidwave coil effecting thereby a wave development on said wave coil, meansfor modulating said source of high potential for purposes of signalling.

ll. A system for transmitting radio signals comprising a wave coilhaving distributed inducta-nce and capacity, said wave coil being in theform ot an open circuit and having a non-metallic core, said wave coilbeing adapted to have wave development produced thereon by theapplication of a high frequency potential to only one element of saidcoil, means for varying the point of application of said potential forthe purpose of obtaining a maximum energy radiation from said wave coil,means for producing said high frequency potential and means formodulating same.

12. A system for transmitting radio signals comprising a multiple layerwave coil having distributed inductance and capacity, said wave coilbeing in the form of an open circuit and having a non-metallic core,said wave coil being` adapted to have a wave development producedthereon by the application of a high frequency potential to only oneelement of said coil, means for varying the point of application of saidpotential for the purpose of obtaining a maximum energy radiation fromsaid wave coil, means for producing said high frequency potential andmeans for modulating same.

13. A system for transmitting radio signals comprising means for causingwave developments on two or more antennae by simultaneously imposingthereon a suitable potential from a single source, the frequencies ofthe two or more wave developments being respectively adjustable byadjustments of the antennae.

J. O. MAUBORGNE. GUY HILL.

